Liquid crystal display substrate glass and preparation method thereof

Abstract

The present invention belongs to the technical field of display glass manufacturing, and particularly relates to a liquid crystal display substrate glass and a preparation method thereof. The liquid crystal display substrate glass comprises the following raw materials: SiO2, Al2O3, BaO, MgO, CaO, SrB4O7, and a composite clarifier; the composite clarifier comprises SnO2 and FeO / SiO2 composite particles; the structure of the FeO / SiO2 composite particles is a structure in which SiO2 covers FeO; the composite clarifier composed of the SnO2 and FeO / SiO2 composite particles improves the clarification effect on glass liquid, avoids excessive use of SnO2, which would form grayish-white tin spots on the glass surface and affect the glass quality; through the combined action of the composite clarifier composed of the SnO2 and FeO / SiO2 composite particles and SrB4O7, the glass raw materials can be melted more evenly, have a good clarification effect, and have a low thermal expansion coefficient and shrinkage rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of display glass manufacturing, and in particular relates to a liquid crystal display substrate glass and a preparation method thereof. Background Art

[0002] Liquid crystal displays (LCDs) are currently the most popular display device, offering advantages such as low power consumption, low radiation, flicker-free screens, light weight, and compact size. Alkali-free high-aluminum borosilicate glass, with its excellent thermal stability, chemical stability, mechanical properties, and dielectric properties, is an ideal substrate material for LCDs. However, due to its lack of alkali metals and high aluminum oxide content, alkali-free high-aluminum borosilicate glass has a high viscosity, making it difficult to clarify and prone to microbubble defects. To reduce microbubble defects in the glass, clarifiers are often added to the raw materials.

[0003] Initially, clarifiers such as As2O3 and Sb2O3 were used, but these were gradually phased out due to their potential pollution and harm to humans and the environment. Later, it was discovered that SnO2 decomposes at temperatures above 1400°C to produce SnO and O2. Upon cooling, SnO oxidizes, consuming O2. This provides a better bubble-removing and clarification effect. However, a high SnO2 content alone is required to achieve the desired clarification effect, and it can also form grayish-white tin spots on the glass surface, affecting its quality.

[0004] At present, most composite clarifiers are composed of two or more of SnO2, sulfate, halide and boron oxide, which reduces the SnO2 content. However, halide and boron oxide are high-temperature volatile agents that participate in glass clarification. The volatilization of halide or boron oxide will cause uneven melting of glass raw materials, increase the thermal expansion coefficient of glass, cause large thermal shrinkage of glass, and easily warp and deform during the molding process. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a liquid crystal display substrate glass and a preparation method thereof, wherein the glass raw materials melt more uniformly, have a good clarification effect, and a lower thermal expansion coefficient.

[0006] The present invention provides a liquid crystal display substrate glass, comprising the following raw materials in percentage by weight:

[0007] SiO2 50%-65%, Al2O3 15%-30%, BaO 0.1%-10%, MgO 0.1%-10%, CaO 0.1%-10%, SrB4O7 0.1%-10%, composite clarifier 0.15%-0.65%; the composite clarifier includes SnO2 and FeO / SiO2 composite particles; the structure of the FeO / SiO2 composite particles is a structure of SiO2 coating FeO.

[0008] Optionally, the content of SnO2 in the raw material is 0.06%-0.15%, and the content of FeO / SiO2 composite particles is 0.1%-0.5%.

[0009] Optionally, a liquid crystal display substrate glass comprises the following raw materials in percentage by weight:

[0010] SiO251%-57%, Al2O318%-22%, BaO 5%-8%, MgO 5%-8%, CaO 5%-7%, SrB4O74%-6%, SnO20.1%-0.13%, FeO / SiO20.2%-0.45%.

[0011] Optionally, the method for preparing the FeO / SiO2 composite particles comprises the following steps:

[0012] FeO is dispersed in a mixed system of silica sol and organic solvent, and then dried and pulverized using a spray dryer to obtain FeO / SiO2 composite particles coated with silica.

[0013] Optionally, the particle size of the FeO is 5-20 μm.

[0014] Optionally, the weight percentage of silicon dioxide in the silicon dioxide sol is 20%-40%.

[0015] Optionally, the mass ratio of FeO to silica sol is 1:2.5-6.

[0016] Optionally, the particle size of silica in the silica sol is 20-35 nm.

[0017] Optionally, the Al2O3 is replaced by a mixture of Al2O3 and Al(OH)3.

[0018] The present invention provides a method for preparing the liquid crystal display substrate glass, comprising the following steps:

[0019] The raw materials are first heated to 1400℃-1500℃ in a furnace, kept warm, and subjected to the first stage of homogenization and clarification. They are then heated to above 1600℃ and subjected to the second stage of homogenization and clarification. The glass liquid is then formed into the desired shape through an overflow method to obtain liquid crystal display substrate glass.

[0020] Optionally, the holding time of the first stage homogenization and clarification is 1.5-3 hours, and the holding time of the second stage homogenization and clarification is 2-5 hours.

[0021] The beneficial effects of the present invention are that the composite clarifier composed of SnO2 and FeO / SiO2 composite particles improves the clarification effect on glass liquid, reduces the amount of SnO2 added, avoids excessive use of SnO2, and prevents the formation of grayish-white tin spots on the glass surface that affect the glass quality. It also avoids the problem of uneven melting of raw materials caused by volatile clarifiers, and has a certain effect of improving Young's modulus.

[0022] SrB4O7 significantly reduces thermal expansion and shrinkage, and improves Young's modulus to a certain extent, without any other adverse effects. The combined action of a composite clarifier composed of SnO2 and FeO / SiO2 composite particles, along with SrB4O7, results in a more uniform melting of the glass raw materials, achieving excellent clarification and lower thermal expansion and shrinkage. DETAILED DESCRIPTION

[0023] The present invention provides a method for preparing FeO / SiO2 composite particles, comprising the following steps:

[0024] FeO and silica sol (silicon dioxide content is 30%) are taken in a mass percentage of 1:4, the particle size of FeO is 5-20μm, and the particle size of silica is 20-35nm, and they are dispersed in ethanol. Then, a spray dryer is used to dry and pulverize them to obtain FeO / SiO2 composite particles.

[0025] Example 1

[0026] Preparation of liquid crystal display substrate glass:

[0027] The raw materials, calculated by weight percentage: SiO2 56%, Al2O3 20%, BaO 6.6%, MgO 6%, CaO 6%, SrB4O 75%, SnO2 0.1%, and FeO / SiO2 composite particles 0.3%, are first heated to 1410°C in a furnace and kept warm for 2 hours for the first stage of homogenization and clarification, then heated to 1660°C and kept warm for 3 hours for the second stage of homogenization and clarification. The glass liquid is then formed into the desired shape by an overflow method to obtain liquid crystal display substrate glass.

[0028] Example 2

[0029] Preparation of liquid crystal display substrate glass: SiO2 55.8%, Al2O3 20%, BaO 6.6%, MgO 6%, CaO 6%, SrB4O 75%, SnO2 0.1%, FeO / SiO2 composite particles 0.5%, and the rest is the same as in Example 1.

[0030] Example 3

[0031] Preparation of liquid crystal display substrate glass: SiO2 60%, Al2O3 16%, BaO 9.77%, MgO 3%, CaO 3%, SrB4O 78%, SnO2 0.05%, FeO / SiO2 composite particles 0.18%, and the rest is the same as in Example 1.

[0032] Example 4

[0033] Preparation of liquid crystal display substrate glass: SiO2 51%, Al2O3 21%, Al(OH)34%, BaO 6.6%, MgO 6%, CaO 6%, SrB4O 75%, SnO2 0.1%, FeO / SiO2 composite particles 0.3%, and the rest is the same as in Example 1.

[0034] Comparative Example 1

[0035] Preparation of liquid crystal display substrate glass: SiO2 56.3%, Al2O3 20%, BaO 6.6%, MgO 6%, CaO 6%, SrB4O 75%, SnO2 0.1%, without adding FeO / SiO2 composite particles, and the rest is the same as Example 1.

[0036] Comparative Example 2

[0037] Preparation of liquid crystal display substrate glass: SiO2 56.14%, Al2O3 20%, BaO 6.6%, MgO 6%, CaO 6%, SrB4O 75%, SnO2 0.1%, FeO 0.16% (converted from Example 1), and the rest is the same as Example 1.

[0038] Comparative Example 3

[0039] Preparation of liquid crystal display substrate glass: SiO2 55.5%, Al2O3 20%, BaO 6.6%, MgO 6%, CaO 6%, SrB4O 75%, SnO2 0.1%, FeO / SiO2 composite particles 0.8%, and the rest is the same as in Example 1.

[0040] Comparative Example 4

[0041] Preparation of liquid crystal display substrate glass: SiO2 56%, Al2O3 20%, BaO 6.6%, MgO 6%, CaO 6%, SrO5%, SnO2 0.1%, FeO / SiO2 composite particles 0.3%, and the rest are the same as in Example 1.

[0042] The strain point, average thermal expansion coefficient, Young's modulus, specific modulus, and number of bubbles per unit mass of the liquid crystal display substrate glass obtained in each group were tested. The results are shown in Table 1.

[0043] Table 1

[0044]

[0045] By comparing Examples 1-4 with Comparative Examples 1 and 2, it can be seen that the composite clarifier composed of SnO2 and FeO / SiO2 composite particles improves the clarification effect on the glass liquid and reduces the amount of SnO2 added. It can avoid excessive use of SnO2, which forms grayish-white tin spots on the glass surface and affects the glass quality. It also avoids the problem of uneven melting of raw materials due to volatile clarifiers, and has a certain effect of improving Young's modulus. It can be seen from Comparative Example 3 that the content of FeO / SiO2 composite particles needs to be strictly controlled, and excessive amount will reduce the transmittance of the glass.

[0046] Comparative Example 4 shows that SrB₄Oₐ significantly reduces the thermal expansion coefficient and shrinkage, and also has a certain effect of increasing Young's modulus, without causing any other adverse effects. Therefore, the combined action of the composite clarifier composed of SnO₂ and FeO / SiO₂ composite particles and SrB₄Oₐ can achieve more uniform melting of the glass raw materials, achieve good clarification, and achieve a lower thermal expansion coefficient and shrinkage.

[0047] It can be seen from Examples 1 and 4 that replacing a small amount of Al2O3 with Al(OH)3 can reduce the bubble content of the glass.

[0048] The working principle of the composite clarifier of the present application is as follows: in the first stage, the temperature is heated to 1400°C-1500°C, FeO is coated by SiO2 and will not be prematurely oxidized, SnO2 decomposes to produce SnO and O2, O2 absorbs and combines other gases in the glass liquid, causing the bubble volume to increase, accelerating its rise, and discharging other gases and most of the O2, thereby achieving the purpose of clarification; in the second stage, the temperature is heated to above 1600°C, SiO2 in the FeO / SiO2 composite particles melts, causing FeO to react with oxygen bubbles with smaller diameters that are difficult to discharge, generating Fe2O3 and consuming O2; when the glass liquid is formed into the desired shape by the overflow method, the temperature is lowered, SnO reacts with the residual O2, and returns to SnO2, further consuming the remaining oxygen bubbles and improving the glass clarification effect.

[0049] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of protection of the present application is limited to these examples. In line with the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0050] The one or more embodiments of this application are intended to encompass all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this application should be included in the scope of protection of this application.

Claims

1. A liquid crystal display substrate glass, characterized in that: The following raw materials are included in weight percentage: SiO2 50%-65%, Al2O3 15%-30%, BaO 0.1%-10%, MgO 0.1%-10%, CaO 0.1%-10%, SrB4O 75%-8%, composite clarifier 0.15%-0.65%; the composite clarifier includes SnO2 and FeO / SiO2 composite particles; the structure of the FeO / SiO2 composite particles is SiO2 coated with FeO; The content of SnO2 in the raw materials is 0.06%-0.15%, and the content of FeO / SiO2 composite particles is 0.1%-0.5%.

2. The liquid crystal display substrate glass according to claim 1, wherein: The following raw materials are included in weight percentage: SiO2 51%-57%, Al2O3 18%-22%, BaO 5%-8%, MgO 5%-8%, CaO 5%-7%, SrB4O7 5%-6%, SnO20.1%-0.13%, FeO / SiO2 0.2%-0.45%.

3. The liquid crystal display substrate glass according to claim 1, wherein: The method for preparing the FeO / SiO2 composite particles comprises the following steps: FeO is dispersed in a mixed system of silica sol and organic solvent, and then dried and pulverized using a spray dryer to obtain FeO / SiO2 composite particles coated with silica.

4. The liquid crystal display substrate glass according to claim 3, wherein: The particle size of the FeO is 5-20 μm.

5. The liquid crystal display substrate glass according to claim 3, wherein: The weight percentage of silicon dioxide in the silicon dioxide sol is 20%-40%.

6. The liquid crystal display substrate glass according to claim 3, wherein: The mass ratio of the FeO to the silica sol is 1:2.5-6.

7. The liquid crystal display substrate glass according to claim 3, wherein: The particle size of the silicon dioxide in the silicon dioxide sol is 20-35 nm.

8. A method for preparing a liquid crystal display substrate glass according to any one of claims 1 to 7, characterized in that: The following steps are involved: The raw materials are first heated to 1400-1500°C in a furnace, kept warm, and subjected to the first stage of homogenization and clarification. They are then heated to above 1600°C and kept warm for the second stage of homogenization and clarification. The glass liquid is then formed into the desired shape by an overflow method to obtain liquid crystal display substrate glass.

9. The method for preparing a liquid crystal display substrate glass according to claim 8, wherein: The holding time for the first stage of homogenization and clarification is 1.5-3 hours, and the holding time for the second stage of homogenization and clarification is 2-5 hours.

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